Convert RFA to 3MF in your application
3D InterOp is a CAD interoperability SDK that lets your software read RFA files and write 3MF, generating the 3MF mesh from the geometry it reads, with tessellation settings your application controls.
Spatial does not offer an online converter or a desktop conversion app. 3D InterOp is a component that software vendors embed in their own products.
- Reads Revit family · Writes 3MF
- Mixed geometry → triangle mesh
- C++ / C# APIs
RFA to 3MF at a glance
Revit family can mix exact solids and facets; 3MF stores triangles only, so the whole model is tessellated when it is written.
| Revit family (source) | 3MF (target) | |
|---|---|---|
| Full name | Revit family | 3D Manufacturing Format |
| Standard / owner | Autodesk | 3MF Consortium, ISO/IEC 25422 |
| File extensions | .rfa | .3mf |
| Geometry | B-Rep and mesh (read); mesh (written by 3D InterOp) | Triangle mesh |
| Assemblies / structure | Nested families; assembly structure written by 3D InterOp | Objects and build items |
| 3D InterOp support | Read and write | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from Revit family to 3MF.
-
Changes
Geometry is tessellatedThe exact Revit family B-Rep is replaced by a triangle mesh, generated by 3D InterOp from the exact geometry it reads. Accuracy depends on the tessellation settings your application uses.
-
Changes
Assembly structure3MF has no native assembly hierarchy. Decide in your application how Revit family product structure is grouped or flattened before writing.
Why software vendors add RFA to 3MF conversion
Additive manufacturing
3MF is still the input most slicers and print services expect. Writing it lets your users send parts to print directly.
Mesh-based processing
Inspection, scan comparison and mesh-editing tools work on triangles. A mesh output gives them a model they can open anywhere.
Lightweight sharing
A mesh is simpler than the native CAD file and needs no CAD system to open.
Things to check before you ship
- Written 3MF versions: 3MF 1.1.
- The 3MF writer is available through the UConnect interface only.
- Supported RFA input: Revit 2015 to 2026.
- Test tessellation settings on your heaviest parts: finer meshes mean larger files.
- Validate a sample of translated files in the target system your users actually work with.
Working with Spatial was a real milestone for us: Thanks to the powerful 3DInterOp library, we were able to successfully bring our complex CAD-based solutions to the cloud while remaining flexible to meet individual customer requirements. For us, Spatial is not just a technology partner, but a true enabler of our product strategy.
Dr. Arno Michelis, Founder, Simus Systems
Read the Case StudyAbout the formats
-
Source format
What is an RFA (.rfa) file?
An RFA file is a Revit family: a reusable component such as a door, a window or a piece of equipment, with its geometry, types and parameters, loaded into Revit projects.
-
Target format
What is a 3MF (.3mf) file?
3MF is an open format for additive manufacturing, defined by the 3MF Consortium. It stores triangle meshes with units, colors and build information in a single package.
Frequently asked questions
3D InterOp tessellates the geometry it reads from RFA when it writes 3MF. Your application sets the tolerances, so it controls the trade-off between accuracy and file size.
3MF has no assembly hierarchy, so your application decides how the RFA structure is grouped or flattened before writing.
The 3MF writer is available through the 3D InterOp UConnect interface.
3D InterOp reads Revit 2015 to 2026.
3D InterOp writes 3MF 1.1.
Yes. 3D InterOp reads and writes both formats, so 3MF to RFA is supported too.
-
Building software that needs to convert RFA to 3MF?
3D InterOp is an SDK that lets your application read Revit family and write 3MF alongside 30+ CAD and BIM formats.